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  4. CVE 2026 88806 libx11 xkbgetmap reply heap based buffer overflow
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Back to active CVEs
High · CVSS 7.5CVE-2026-88806

libX11 XkbGetMap Reply Heap-based Buffer OverflowCVE-2026-88806

Answer in brief

CVE-2026-88806 records a High severity (CVSS 7.5) vulnerability in libX11 XkbGetMap Reply Heap-based Buffer Overflow. The current sources do not mark it as known exploited. The current feed maps x.org/libX11 (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 21, 2026Updated Sep 22, 2026Source checked Nov 5, 2026First seen by HOL Sep 21, 2026Material review Sep 22, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 7.5
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Available

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps x.org/libX11 (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
x.org/libX11generic>=0 <1.8.141.8.14

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for x.org/libX11.
  2. 2Review the reported fix. Update x.org/libX11 to 1.8.14 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Sep 21, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Sep 22, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Sep 21, 2026

Sources and claim methodology

  • Source referencegitlab.freedesktop.org
Upstream source description

A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Gdb: gdbserver: heap buffer overflow in cmd_qtdpsrc via qtdpsrc declared/actual length mismatchAlso CWE-122

Record context

Vulnerability class
Buffer Overflow
EPSS
Not reported
CWE IDs
CWE-122
Source
CVE List V5
Source checked
Nov 5, 2026
References
1 linked source
Open source record